1. Field of the Invention
The present invention relates generally to computer systems, and more particularly but not exclusively to content filtering systems.
2. Description of the Background Art
Content filtering systems are employed in computer systems to scan incoming data for malicious content, such as computer viruses, spam, unwanted content, and unauthorized network intrusion. A content filtering system typically includes a pattern file against which data units (e.g., files, packets) are compared. An antivirus program is an example content filtering system that employs a pattern file. The pattern file of an antivirus program contains the patterns or signatures of known computer viruses. An antivirus program compares the contents of an incoming data unit against the contents of a pattern file to determine if the data unit has a virus. A pattern file is periodically updated to include the patterns of newly discovered viruses.
In the event of a computer virus outbreak, antivirus researchers race to develop an antidote for the virus. The antidote is typically in the form of a pattern file that is distributed to computers signed up to receive pattern file updates. Large public networks, such as the Internet, allow a computer virus to rapidly spread throughout the world. This makes it imperative to distribute antidotes before large number of computers have been infected or otherwise damaged by the virus.